In recent years, a great deal of public attention has been focused upon the environmental effects of the use of fossil fuels, such as gasoline, in automobiles and other vehicles. This attention has focused in part on the effects the vapors produced by these fuels have on the environment, and in part on the vehicle emissions produced by the burning of these fuels. To reduce these fuels' harmful environmental effects, new environmental standards have been implemented. These standards have included the Clean Air Act of 1990 which mandated the use of vacuum-assisted (VA) vapor recovery systems at retail gasoline facilities. In VA systems, means are incorporated on the nozzle for recovering vapor from the vehicle fuel tank back to the underground fuel storage tank. In one widely employed vapor recovery system, a bellows is telescoped over a nozzle spout to form a coaxial vapor return passage in combination with the nozzle spout. The free end of the bellows sealingly engages the fuel fill pipe so that vapor displaced from the tank is captured in this passage. The vapor then passes, through the body of the nozzle, to a coaxial hose. The coaxial hose has an inner hose through which fuel passes and an outer, coaxial, spaced hose which defines a vapor passage through which the fuel vapor passes to the dispenser and then back to the storage tank. To date, VA systems have been widely implemented at retail gasoline facilities, and it is estimated that up to 700,000 hose point systems could be in place by the year 2000.
More recently, additional legislation has mandated that On Board Refueling Vapor Recovery systems or "ORVRs" be implemented on all new automobiles and light trucks beginning in the year 1998. In an ORVR system, a carbon canister is installed on the vehicle to absorb the vapors produced during refueling. These ORVR systems are intended to replace the existing VA vapor recovery systems and increase the ability to recover vapors which are normally produced during vehicle refueling at a pump or dispenser. With the impending transition from vacuum-assisted systems to ORVR's, several key technical issues have emerged. At the forefront of these issues is the incompatibility of the current vacuum-assisted vapor recovery system and the proposed ORVR systems. If development work on the ORVR systems continues in its current direction, a liquid seal in the auto fillpipe will direct fuel tank vapors to the on-board canister in the vehicle. In the case of a dispenser with a VA system refueling an ORVR equipped vehicle, the VA system will ingest fresh air at the nozzle and pump the air back to the underground storage tank. This fresh air will saturate in the underground storage tank, causing gasoline vapor growth and a pressure increase in the tank, to the point of opening the pressure vacuum vent. When this happens, fugitive emissions are created, partially offsetting the benefits derived from collecting the refueling vapors in the on-board canister.
Accordingly, in the future, as vehicles begin to be produced with on-board canisters, it will be necessary to have a system for determining at the refueling point, whether a vehicle has been equipped with an onboard canister. If the vehicle does have an onboard canister or ORVR, the dispenser VA system could be shut-off during the refueling operation to prevent fresh air from being ingested into the system. Likewise, if the vehicle is not equipped with an ORVR, the dispenser VA system could be made operative to capture vapors during fueling.
Another "environmentally friendly" alternative that has been proposed to reduce smog producing VOC emissions is the use of alternative fuels. Methanol is a leading alternative fuel contender at this time, because it produces lower emissions than traditional gasoline. However, a key issue surrounding the widespread adoption of alternative fuels is how to properly identify methanol fueled vehicles at the refueling point to prevent accidental misfueling of a vehicle. An improper identification of a vehicle's fuel can result in the vehicle being rendered inoperable. Accordingly, it is essential to have an accurate and reliable system for determining vehicle fuel requirements. Solutions that have been proposed in the past to solve the problem of identifying methanol vehicles have included unique nozzle spout shapes and card/key lock systems to authorize refueling. However, these applications have proven to be impractical to implement on a wide scale. Accordingly, it is desirable to have a practical, convenient system for identifying alternative vehicles that is capable of being implemented on a wide scale basis.
RF identification systems have been provided in the past which have enabled a base station to interrogate any of a number of vehicles in a fleet in order to obtain vehicle and operator information. However, up until now, it has not been possible to utilize these systems in refueling stations due to safety concerns. According to prior systems, in order to generate an RF signal to interrogate a vehicle, a high power signal would need to be transmitted to the nozzle through the fuel hose. Due to the highly flammable nature of the fuel and vapor passing through the hose, this high power signal would create an unreasonable risk of fire, and hence, render the system too dangerous for use.
Thus, a need exists for a vehicle identification system which can be used to identify alternative fuel vehicles and obtain other vehicle information, yet which is safe for use in a vehicle refueling station.